Traffic signaling system



- name, 196 M.=JEFFER Y 31 ,434,742:

'flywnc SIGNALING SYSTEM Filed Iay'lQ, 1966 4 Sheet-548M611 2 4 s s; a s

INVENTOR. Q WALTER 1A.. JEFFERS.

ATTORNEY.

Dec, 16, 969 I 'w. M. JEFFERS I I TRAFFIC. SIGNALING SYSTEM v 4Sheets-Sheet s 'Filed Hay 19L 1966 mam INVENTOR. WALTER H. JEFFERS.

ATTORNEY.

16,1969 WMJEFFERS 3,484,742

TRAFFIC simmmuc SYSTEM F iled'hlay 19 196.6- 4 Sheets-Sheet; 4

INVENTOR- WALTER u. JEFFERS.

ATTORNEY.

United States Patent York Filed May 19, 1966, Ser. No. 551,428 Int. Cl.G08g /00; H04q 1/00 US. Cl. 340-40 4 Claims ABSTRACT OF THE DISCLOSUREDisclosed is a traffic signal system for a multiplicity of intersectionswherein a variable cycle time master timer produces 100 stepping pulses,a zero pulse, and positive and negative polarity potentials mainfestingthe half cycle sector of the timer on each of three wires connected toeach intersection controller. A single decimal counter with a capacityof 100 counts has a plugboard associated therewith for predeterminedsplits, and settable switches for determining offset. The counter isnormally stepped by the stepping pulses, and upon coincidence with eachsplit count activates the next traffic movement. The offset switches incooperation with the counter produce two controls, one at the presetoffset count and the other at the offset count +50 (180 later) which,together with the zero pulse and the positive and negative potentialsfrom the master timer, set storage devices to maintain the counter,advance the counter or retard it, by respectively allowing free passagesof the stepping pulses, gating additional pulses thereto from a localpulser, or withholding the stepping pulses so as to bring the countergradually into phase synchronism with the master.

This invention has to do with highway traffic signaling, and inparticular with an interconnect system for controlling a multiplicity ofsecondary traffic signal control lers in the system.

The invention has as an object an interconnect system involving a uniquearrangement for actuating the secondary controllers of the system fromone movement to the next, for providing a selected one of severaldifferent ofisets between a secondary controller and the master timer,for checking the offset relationship between the secondary controllerand the master timer a number of times during each cycle of the mastertimer, and for advancing, or retarding, a secondary controller byrelatively small increments during a cycle of the master timer dependingon whether the secondary controller is running ahead, or behind, themaster.

This invention may be used as an interconnect system for the secondarycontrollers, as disclosed in my Patent No. 3,208,038, issued Sept. 21,1965. The interconnect system for this invention takes the place of thethree dial motors 261, 262, 263 in said patent.

In general, the interconnect system includes a variable speed cyclicallyopera ed master time which functions to produce a multiplicity ofequally and closely spaced pulses during each cycle of its operation. Apulse counter is associated with each secondary controller for countingthe pulses transmitted from the master timer. The system also includesmeans for selecting certain ones of the counted pulses and transmittingthe selected counted pulses to the secondary controller and, upon thetransmission of a selected common pulse, the secondary controller willbe advanced from one major movement to the next. Accordingly, asecondary controller is operated by the selected counted pulses toprovide a desired split for each cycle or total period of the mastertimer and accordingly, such pulses may be referred to as split pulses.

The master timer also functions to energize other cir- 3,484,742Patented Dec. 16, 1969 cuits during different parts of the cycle. Theseother circuits serve to check the relationship, or offset, between themaster timer and a secondary controller and, in the event the secondarycontroller is not in synchronism with the master timer at the desiredoffset, means is provided for adding to, or subtracting from, the splitpulses fed to the counter, whereby the counter will count faster, orslower, than normal to cause the controller to advance, or retard,relative to the master timer until the two are in synchronism at thedesired oflset.

In describing this invention, reference is had to the accompanyingdrawings in which like characters designate corresponding parts in allthe views.

In the drawings:

FIGURE 1 is a block diagram of my system.

FIGURE 2 is a side elevational view of a master timer arrangement whichmay be used in my system.

FIGURE 3 is a view illustrating the relative position in which thepulsing disks of the master timer are mounted on the disk shaft.

FIGURE 4 is a diagram of the switching arrangement for selectingdifferent offset and split functions.

FIGURE 5 is a schematic wiring diagram of the pulse counting and offsetselector arrangement.

FIGURE 6 is a schematic diagram of the circuity involved in the splitselector.

FIGURE 7 is a schematic wiring diagram of the offset selector circuity.

FIGURE 8 is a fragmentary sectional view of a plug board taken on a linecorresponding to line 88. FIG- URE 6.

FIGURE 9 is a schematic wiring diagram of the amplifier arrangementbetween the counter and the secondary controller.

A form of master pulsing timer is schematically shown in FIGURES 2 and3. In this arrangement, disks 20, 21, 22, 23, are fixedly mounted on ashaft 24 journalled in bearing supports 25, 26. The shaft 24 is rotatedin counterclockwise direction, FIGURE 3, by a motor 28 which is of thevariable speed type.

The disk 20 is formed with a multiplicity of slots 27. In a practicalembodiment of this invention, the disk 20 was provided with of the slots27, which were equally spaced circumferentially around the disk. A lightsource 30' is mounted at one side of the disk 20 and arranged to projecta beam through the slots 27 to a photo cell 31.

A disk 21 is formed with a slot 33, which extends circumferentialy ofthe disk slightly less than The disk 22 is formed with similar slot 35,the slot 35 being offset 180 from the slot 33. The disk 23 is formedwith a slot 36 which, in circumferential dimension, is only a fractionof the slots 33, 35.

A light source 37 and a photo cell 38 is provided for the disk 21. Alight source 40 and a photo cell 41 is provided for the disk 22, and alight source 43 and a photo cell 44 is provided for the disk 23. Thelight sources 30, 37, 40 and 43, are energized continuously from the hotfeed 45.

As each slot 27 is moved into registration between the light source 30and the photo cell 31, a pulse is transmitted through conductor 47,amplifier 48, to wire 49. During the time the slot 33 in disk 21 ismoving intermediate the light source 37 and the photo cell 38, currentis supplied to the conductor 50, to amplifier 51, to wires 52, 53.During the time the slot 35 is positioned intermediate the light source40 and photo cell 41, power is supplied to the conductor 54, amplifier55, wire 56, to wire 53. Actuation of photo cell 44 by light from lamp43 passing through slot 36 of disk 23, provides power to conductor 57,amplifier 58, wire 59. The output of amplifiers 48, 51 and 58 ispositive. The output from amplifier 55 is negative.

The pulses impressed on conductor 49 are transmitted through an offsetcontrol unit, shown in FIGURE 7, to a pulse counting means, shown in theupper portion of FIGURE 5. The pulse counter functions to count thepulses impressed on it and, as will appear later, means is provided forselecting certain of the counted pulses for actuating the local trafiicsignal controller.

In the embodiment disclosed in FIGURE 5, the counter consists of twoDekatron multi-cathode glow tubes, which are particularly convenientbecause they give a visual indication of the count, as well as anelectrical output for each count. Bulletin D-4009, published byBaird-Atomic Inc., 1961, may be referred to for the specific structuralarrangement of these tubes.

The counter tubes are indicated at 60, 61, and are so connected in thecircuit as to provide two decades for counting the pulses continuously.The disk 20 is formed with 100 slots 27. Each pulse impressed onconductor 47 moves the unit decade, tube 61, forward one step. On thetenth count, the unit decade 61 sends a pulse to the tens decade 60,advancing it one step. The ten cathodes of each counter tube arenumbered to 9. In the arrangement shown in FIGURES and 6, plug boardsare employed as a convenient means for selecting split pulses to betransmitted to the secondary controller. The cathodes of the tenscounter tube 60 are connected to a plug board 63, FIGURE 6, and thecathodes of the units counter tube 61 are connected to a plug board 64.These plug boards 63, 64, are provided with vertically extendingconducting strips VSO to V59. There are horizontal conducting stripsHS1HS10 located rearwardly of the vertical strips, see FIGURE 8. Theboards and the strips VS and HS are formed with aligned apertures 67 forthe reception of a conducting plug 68. In this manner, any verticalstrip may be electrically connected to any horizontal strip.

The cathodes 09 of the tens tube 60 are connected to the vertical stripsVSO-VS9 of the board 63, and the cathodes of the unit counter tube 61are similarly connected to the vertical strips of the board 64. A wire70 extends from the zero cathode of the tube 60 to wire 71, which isconnected to the vertical strip VSO on board 63. The bottom of thisstrip is connected by wire 73 to diode 74.

A wire 77 extends from the zero cathode of tube 61 to the vertical stripVSO of board 64, and the bottom of that strip is connected to diode 78.Attention is called to the fact that each of the cathodes of the tubes60, 61, are connected by resistors 79, to the ground wire 80.

The diodes 74, 78, are connected back to back to form a conventional ANDcircuit, the junction 81 of which is connected by wire 82 to anamplifier 83, the output 84 of which extends to the secondary controllerand, when provided with power, is effective to move the secondarycontroller out of its first movement. All the horizontal strips HS1HS10of the plug boards are also connected to diodes arranged in back to backform to provide AND circuits. The amplifier arrangement is shown inFIGURE 9. The wire 82 extends to the grid of the tube V of theamplifier. A positive supply of twenty volts is fed to the grid throughthe resistors 85, 86. The counter tube cathode resistors are in theorder of one hundred K, and the resistor 85 is tWo megohms. Accordingly,the potential on the grid of V10 will be maintained below that whichwill fire the tube. However, when the diodes 74, 78, are blocked by aselected count, as by the count zero-zero, FIGURE 9, by the thirty voltplus output of the counter tubes, the potential on the grid of V10 willraise sufficiently to fire the tube. With V10 conducting, relay 87 ispulled in, closing the contacts 88, 89, to transmit power from thesource 97, through Wire 84, to the secondary controller.

The remaining cathodes 1-9 of the tens tube 60 are connected to theremaining vertical strips VSl-VS9 of the board 63 by wires 101-109. Theremaining cathodes 19 of the units tube 61 are connected to theremaining vertical strips VS1-VS9 of the unit board 64 by wires 111119.

Referring to FIGURE 6, the horizontal strips HS1- HS10 of each of theboards 63, 64, are connected together through a pair of diodes toprovide an AND circuit, as in the case of the diode circuit 74, 78. Forexample, the top horizontal strips HSl of the boards are connected tothe diodes 121.

Referring to FIGURE 6, a plug 68 is inserted in the tens board 63 toconnect the vertical strip V53 with the horizontal strip HSI. A plug 68is inserted at the junction of strip VSl, and the horizontal strip H81,in the board 64. As the disk 20 rotates from zero position to slotnumber 30, the ten tube 60 has been advanced so that the cathode number3 thereof provides power to the horizontal strip HS1 of the tens boardto the diode 120. When the disk rotates to bring the next slot intoregistration with the photo cell 31, a pulse is emitted from the No. 1cathode of the unit tube 61. With the plug 68 positioned, as stated, inthe board 64, this pulse is transmitted to the diode 121. The junction122 between the diodes 120, 121, is connected by wire 123, throughclosed contacts 124, 125, of relay 126. Contact 125 is connected by wire127 to contact 128 of relay 209. This contact is engaged by contact 220to provide power through wire 132 to amplifier 133, the output 134 ofwhich extends to the secondary controller to move it out of its secondmovement. It will be recalled that with the disk 20 in zero position,power was supplied to the secondary controller through conductor 84 toterminate the first movement of the controller.

Referring further to FIGURE 6, there is a plug 68 inserted at thejunction of the horizontal strip HS2 and the vertical strip VS6 in thetens board 63. A plug is also inserted in board 64 at the junction ofthe horizontal strip HS2 and the vertical strip VS2. It will be apparentthat when the disk 20 has rotated further to produce sixty pulses to thecounters, cathode number 6 of the tens tube will be energized and twoslots later cathode number 2 of the units tube will be energized,whereby diodes 137, 138 will be blocked. The junction 140 between thesediodes is connected by wire 141, through closed contacts 142, 143, ofrelay 126, through wire 144, closed contacts 228 of relay 209, to wire147, amplifier 148, the output of which extends to the secondarycontroller to terminate the third movement thereof.

In the arrangement shown, the secondary controller is set up for a cycleof three movements and from the description so far, it will be apparentthat upon a complete rotation of the disk 20, the secondary controlleris actuated successively through the three movements. The amplifiers133, 148 are similar to the amplifier 83.

With the plug arrangement above described, the first movement of thesecondary controller is terminated at the zero count, the secondmovement at the count of 31, and the third movement at the count of 62.

It will be now apparent that the secondary controller cycle may be givenmany different split arrangements, depending on the insertion of theplugs 68 into the apertures 67 of the plug boards 63, 64.

The relays 126, 209, shown at the right center of FIG- URE 6, and thethree relays shown below, are split selector relays. These relays may beoperated from the location of the master timer, or other remote point,to efiect the selection of other splits. Basically, this is accomplishedby inserting additional sets of the plugs 68 in the plug boards, and therelays function to shift the board outputs from one set of plugs toanother. For example, it will be apparent, from the above description,that with relays 126, 209, de-energized, the four plugs positioned, asdescribed above, provide for the split 0-31-62.

To illustrate a different split arrangement, a feed is placed upon wire155, FIGURE 6. This may be done by moving contact 156 into engagementwith contact 157,

FIGURE 4. The switch contacts 156, 157 may be located at the mastertimer. This feed closes relay 158, through diode 159. The opposite sideof the relay coil is connected to a common return 160. Energization ofrelay 158 produces no effect until relay 161 is energized through wire163. Wire 163 is energized simultaneously with one of the signalcircuits from the secondary controller. Normally, this would be upondisplay of the amber signal following the termination of the greensignals first movement. The relatively brief closure of relay 161, incombination with the already closed relay 158, transmits a hot feed fromwire 165, through contacts 166, 167, of relay 158, wire 168, contacts169, 170, of relay 161, to wire 171, relay coil 126, the opposite sideof which is connected through wire 173, to the ground wire 174, theconnection to ground being through resistor 175. Relay 126 is locked infrom the supply 165, by way of contacts 178, 179. Contact 143 is nowmoved into engagement with contact 180, which is connected by wire 181to the junction 182 between the diodes 183, 184, connected to thehorizontal strips HS4 of the boards 63, 64. Contact 125 is moved intoengagement with contact 187, which is connected by wire 188, to thejunction 190 between the diodes 191, 192, connected to the horizontalstrips H83 of both boards.

There is a plug 68A inserted in the junction of the horizontal strip H83and the vertical strip VS3 in board 63. Another plug 68A is inserted inthe junction of horizontal strip H53 and vertical strip VS8 in the board64. There is also a plug 68A inserted in the junction of strips H84 andVS6 in board 63, and a plug 68A is inserted in the junction of stripsH54 and VS7 in board 64. Accord ingly, energization of the relays 158,161 results results in transferring the second and third movement of thetratfic signal controller to a different count-namely, 38 and 67. Toreturn the operation of split L, the relay 158 is de-energized. When therelay 161 is again energized with the amber signal, the relay 126 isshorted out because contact 167 of de-energized relay 158 is nowconnected to the ground wire 174. Accordingly, relay 126 will release.

A third split may be obtained by moving the contact 156 into engagementwith contact 200, FIGURE 4, to impress a negative supply on wire 155.This supply will pull in relay 201, through diode 202. After relay 161is again energized with the amber signal, the second and third movementsof the secondary controller are terminated by plugs 68B inserted at thejuncture of the strips HS5 and VS4, and at HS6 and VS7 in board 63.Matching plugs 68B are inserted at the juncture of strips HS5 and VSO,and at the juncture of HS6 and VS2 in board 64.

When relays 201 and 161 are thus energized, contact 203 of relay 201 ismoved into engagement with contact 204, providing a hot feed from line165, to wire 206, through contacts 205, 207, of relay 161, wire 208, torelay 209. Relay 209 is held in by power from line 165, wires 210, 211,closed contacts 212, 213, and Wire 214. The horizontal strips HS5 of theplugs boards are connected to the diodes 215, 216. The junction 217 isconnectedby wire 218, to contact 219, contact 220, wire 132, to,amplifier 133, the output 134 of which terminates the second movement ofthe secondary controller. The horizontal strips HS6 are connected to thediodes 223, 224. The junction 225 is connected by wire 226, throughcontacts 227, 228, to wire 147, amplifier 148, to the output 150, whichterminates the third movement of the secondary controller.

It will be obvious that more of the plugs 68 may be inserted in the plugboards 63, 64, and additional relays may be added to obtain additionalsplits. In other words, the number of splits is limited only by thenumber of horizontal strips HS on the boards, and the number ofswitching relays.

The system also includes means for obtaining different offset relationsbetween the secondary controller and the master timer, and also forchecking the offset twice during each cycle of the master timer.

Referring to FIGURE 5, there are three offset switches 230, 231, 232.These switches are of the rotary type having movable contacts 233, 234and 235, respectively. Each switch has ten fixed contacts. The fixedcontacts of switch 230 are connected to the cathodes of the counter tube60. The switches 230, 231, are cross-wired in order to give anothercounty fifty percent later in the cycle. As shown in FIGURE 5, thecontact 233 of switch 230 is engaged with the number 3 fixed contact,which is connected to the number 3 cathode of the counter tube 60 by thewire 103. Also, by wire 237, the number 8 contact on switch 234 isconnected to the number 3 cathode of tube 60.

The fixed contacts of switch 232 are connected respectively to thecathodes of tube 61. In FIGURE 5, the movable contact 235 is shownengaging the number 5 contact which is connected by the wires 240, 115,to the number 5 cathode of tube 61. Wire 241 extends from the contact233 of switch 230 to supply power through closed contacts 242, 243, ofrelay 245, through wire 247, through contacts 248, 249' of relay 250,wire 251, to the cathode of diode 252, the anode of which is connectedto line CA which extends to the circuitry shown in FIGURE 7. A wire 255extends from the movable contact 234 of switch 231. With contact 234engaging contact 3 of switch 231, a pulse is impressed on wire 255 fromthe number 8 cathode tube 60, due to the fact that the number 3 contactof the switch is connected to wire 108, by wire 257. Wire 255 extendsthrough contacts 258, 259, of relay 245, Wire 260, contacts 261, 262, ofrelay 250, to the cathode of diode 263, the anode of which is connectedto line CC, which also extends to the circuity in FIGURE 7.

Contact 235 of switch 232 is connected by wire 265, through contacts266, 267, wire 268, contacts 269, 270, of relay 250 to the cathode ofdiode 271, the anode of which is also connected to line CC. Also,through wire 272, to the cathode of diode 273, to the output CA.

From the above, it will be apparent that on the count of thirty-five,both diodes 252, 273, will be blocked by the plus feed from cathodes 3and 5. This means that the output CA will be removed from the groundwire 80, FIGURE 5, to which it was connected through the cathoderesistors 79. Also, subsequently at the count of eightyfive, the samesituation will prevail due to the fact that the switches 230, 231, arecross-wired with contact number 3 of switch 231 being connected to thenumber 8 cathode of tube 60. Accordingly, the line CA is blocked fromground at a selected count, such as thirty-five, and at a count fiftypercent later by a count eighty-five. The output circuit CA and CC serveto control the offset selector shown in FIGURE 7 to shift the count rateso that the CA circuit will be controlled by the zero master timercount, instead of a different one.

Referring now to FIGURE 7, the pulses over the line 49 from the mastertimer disk 20 enter at the top left corner of the figure and, if notdetoured to a lower level, proceed to the wire 281, FIGURE 5, to thegrid of tube 282, which serves as an amplifier to feed the pulses to theunits counter tube 61. The zero or ten cathode of tube 61 extends to thegrid of the amplifier tube 283 for the counter tube 60. The plates ofthe tubes 282, 283, are supplied from wire 2 84, and the plates of thecounter tubes are supplied from wire 285. As previously explained, theoperating circuity for the counter tubes is conventional I and forms nopart of this invention.

Wire 49 is connected to a resistor 287, which functions to limittransient currents. Protector P shunts out transient current that maypass the resistor, such as lightening transients. The Zener diode 288does not pass anything below a certain voltage, as five volts. This toprevent pulse counting of noise and small AC voltages, resulting fromdifferences in the various ground pickups which come from neutralconductors. The Zener diode 289 limits the potential to a predeterminedvoltage, as ten volts. The input pulse on wire 49 is in the order ofbetween fifteen and twenty volts.

The section including tubes V1, V2 and V3, serve to omit pulses when thecounter leads the master by one percent to fifty percent. This action isturned on by action of tube V6. The circuitry including tube V4 addspulses when the counter lags the master by between one and fiftypercent. V4 is actuated, or controlled, by V7. Tube V5 and theassociated relay reset tubes V6 and V7, and make tubes V1 and V4non-conductive, when the secondary controller is in step with the mastertimer. Relays SA and SC are operated from line 53 through the lines CAand CC, FIGURE 5, to effect synchronization between the master timer andthe secondary controller.

To explain the operation of the offset control and resynchronizingcircuitry, it will be assumed that the secondary traflic signalcontroller is to operate at zero offset. This means that the movablecontacts of switches 230, 232, FIGURE 5, will be set on the zero fixedcontacts connected to the zero cathodes of the counter tubes.

When a pulse is impressed on line 49 by the zero slot in dial 20 of themaster timer, it is transferred by the counter to the diodes 252, 273,FIGURE 5. As previously explained, this results in blocking line CA toground, through the resistors 79, connected to the zero cathodes of thecounter tubes. This pulse is held by the counter tubes until the arrivalof the next pulse. However, before the next pulse on wire 49 arrives,plus power is applied to line 53, FIGURE 3, by the slot 33 in disk 21moving intermediate the lamp 37 and the photo cell 38. Wire 53, FIGURE7, extends through diode 290, to relay SA, moving contact 291 intoengagement with contact 292, putting a plus twenty volt feed throughwire 293, to capacitor 294, the top of which is connected to diode 295.Normally, plus twenty volts is fed through resistor 296 to the junction297 between the back to back diodes 295, 298. This plus supply, throughdiode 298, can find its way to ground through line CA, through diodes252, 273, through the closed contacts of relays 245, 250, throughswitches 230, 231, 232, through the resistors 79, to ground line 80.Now, with the zero offset selected, diodes 295, 298, are blocked by thezero count from the tubes 60, 61, and the closing of relay SA, throughline 53, the plus twenty is fed from the junction 297 to the diode 300,to the junction 301, through wire 303, to capacitor 304, to the grid oftube V5, causing the same to fire and close relay 305. Through itsclosed contacts 306, 307, the plates of tubes V6 and V7 are connected toground wire 309. This assures de-ionization of the tubes and preventsany offset change. This amounts to an OK, or clearing check.

When slot 50 in disk 20 impresses a pulse on line 49, a plus feed isimpressed on line 255, FIGURE 5, from switch 232, due to thecross-Wiring of switches 230, 231, placing a block on diode 263. At thattime, the slot 35 in disk 22 causes a negative pulse to be placed online 53 which, by the reversely positioned diode 311, establishescurrent through relay SC, to close the same. Closed contacts 312 supplyplus twenty volts to capacitor 313, the top side of which delivers theplus pulse to the cathode of diode 314. Diodes 314, 315, are connectedback to back at junction 316. A block has been placed on diode 315 byline CC. This resulting from the fact that the zero fixed contact ofswitch 231 is connected to contact number 5 of switch 230, by wire 317,FIGURE 5. A pulse now moves from plus twenty through resistor 318, FIG-URE 7, wire 319, diode 320, to the junction 301, again pulsing capacitor304 to fire tube V5. This is the second clearing check showing that thesecondary is in step with the master timer. It will be seen that thediodes 295, 298, and diodes 314, 315, form two AND circuits. Diodes 300,320, make an OR circuit to make tube V5 responsive to either ANDcircuit.

Assume now that the counter is lagging behind the master so that itscount is between fifty and ninety-nine-- for example, at sixty, at thetime the zero slot in disk 20 sends out the zero pulse. It is to be keptin mind that the disks 2023, are all fixed to the shaft 23 and in theangular relationship shown in FIGURE 3, and the disks rotate in acounter-clockwise direction, Nothing affects the continued counting bythe counter tubes 60, 61. When the counter reaches the zero count, thezero slot in disk 20 has since moved out of registration with the lightsource and cell 31. However, a slot, say number forty, in the diskcauses the counters to give a count of zero. In other words, we areassuming the counter was forty counts behind the master timer. Shortlyafter the zero slot in disk 20 moved out of registration with the cell31, the elongated slot 33 in disk 21 moved into registration with cell38, so that a positive pulse was impressed on line 53, pulling in relaySA. However, the pulse impressed capacitor 294, through contacts 291,292, rapidly dissipated. Accordingly, the blocking of line CA, on thecount of zero by the counter, will not cause the plus twenty to pass tocapacitor 304 to fire tube V5. This because with no charge on capacitor294, the junction 297 is connected to ground wire 324, through resistor325. However, the plus twenty volts will now charge capacitor 327. Withrelay SA held energized, the charge on capacitor 327 is impressed on thewire 328 by closed contacts 261, to capacitor 330, and to the grid ofV7.

V7 is a gas tube and normally non-conducting. This results from thecathode current of tube V4, through resistor 331, holding the cathode ofV7 slightly positive. The positive pulse impressed on the grid of V7causes the tube to fire and the tube will maintain conduction untilreset by relay 305 grounding the plate of V7.

Conduction by tube V7 changes the conduction of tube V4. Normally, tubeV4 is conducting because plus twenty volts is impressed on the gridthrough the resistors 333, 334.

A pulser 335 includes a pair of contacts 336 periodically opened andclosed by a constantly running motor 337. The frequency of the operationof the contacts 336 is much lower than the frequency of the pulsesproduced by the disk 20 of the master timer.

When tube V7 is conducting, it increases the drop across the resistor331, with the result that the cathode of tube V4 is at about twentyvolts. Line 338 provides ten volts negative to the pulser contacts 336.Accordingly, upon subsequent closures of the pulser contacts, ten voltsnegative is transferred by wires 340, 341, to capacitor 342, throughresistor 334, to the grid of V4. This reduces the grid voltage to aboutplus ten volts, which is sufficient to lower the plate current of V4, sothat the top of resistor 275 rises toward volts plus feed through theresistor 345, giving a positive pulse through capacitor 346, the pulsepassing through wire 347 and upwardly through wire 348, diode 349, tothe line 281 extending to the counter tubes 60, 61. The effect of thisis that the counters receive an extra pulse upon each closure of thepulser contacts 336 and accordingly, the counter runs faster than normaland in doing so, is catching up with the master.

It will be apparent that the pulses from the pulser 335 are effective aslong as the described circuitry is maintained, and that means untilrelay 305 closes and that, in turn, happens when the selected countedpulse is in step with the master zero pulse. Accordingly, the additionalpulses from the pulser 335 may be sufficient to advance the counters instep with the master while the relay SA is held closed. On the otherhand, energization of the line 53 by the slot 33 in disk 21 may be suchas to overadvance the counter. Whether the counter is advanced farenough during this period to be synchronized with the master, or not farenough, or too far, depends of course on how far the counters were outof step with the master.

It will be apparent that if on the succeeding zero count, or fiftypercent count, the count is exactly in step with the master, relay 305closes, as described previously, and the counter continues on insynchronous operation with the master.

If, on the other hand, at a succeeding zero count, the counter may havebecome a little ahead of the master, say five percent, the CA feed fromthe zero count will coincide with a feed from the master on line 59.This is due to the fact that with the zero count appearing five percentahead of the master, the slot 36 in disk 23 will be positionedintermediate the lamp 43 and the photo cell 44. With the zero count ofthe counter tubes 60, 61, being advanced five percent, line 53 will beenergized with a negative feed due to the overlap of the slot 35 in disk22 with slot 36 in disk 23. Accordingly, relay SC is closed. A wire 350extends from contact 351 of relay SC, through Zener diode 352, to thecoil of relay 353, the opposite side of which is connected by wire 354,to the ground line 355.

Plus ten volts is applied through diode 356, to the wire 350. With lineCA blocked from ground at the zero count, wire 350 is connected throughcontacts 351, 357, of relay SC, and wire 358 to line CA. With the diode252, 273, FIGURE 5, blocked at the zero count, the voltage on line CAnow goes to plus twenty from the supply through resistance 296, diode298, and accordingly the voltage rises to plus twenty on wire 350,increasing the charge on capacitor 375 by ten volts, which applies tenvolts on the grid of tube V6 to make it conductive and this increase ofvoltage on wire 350, also pulls in relay 353. The Zener diode 352 servesto block the ten volts from diode 356 passing to the relay 353. Theenergized line 59 is connected to the armature 360' of relay 353 whichis now moved into engagement with contact 361, transmitting powerthrough line 362 to relay 364, the opposite side of which is connectedto the ground 355. This results in the separation of contacts 365, 366,disconnecting line 49 from wire 367, which is normally connected to line281, through contacts 368, 369, of a relay 370. The counters 60, 61, nowdwell on the zero until the master sends out the zero pulse andimmediately line 53 is switched from the negative supply to the positivesupply from photocell 38, closing the relay 305, as previouslydescribed, and simultaneously slot 36 in disk 23 moves out ofregistration with the photocell 44, de-energizing line 59 and relay 364.The secondary controller and master timer are now again in step.

It will now be assumed that the counter has reached the zero countbetween ten and fifty percent adhead of the master, say twenty-fivepercent. This means that at the zero count from the counter tubes, theslot 33 in disk 21 would be positioned downwardly, the slot 35 in disk22 would be positioned upwardly and likewise, the slot 36 in disk 23would be positioned clockwise from that shown in FIGURE 3, ninetydegrees. Accordingly, with slot 35 in registration with photo cell 41,negative power would be impressed on conductor 53 and relay SC would beclosed at the time of the zero count from the counter tubes. Also, aspreviously explained, at that zero count, line CA will be blocked fromground by the plus pulse on the diodes 252, 273, FIGURE 5. The plus tothe line 350 will rise to fire tube V6. This same situation prevailed inconnection with the explanation above of the dwell period functioning.However, in this instance, the slot 36 is not positioned to actuate thephoto cell 44, so there is no power on line 59 and accordingly, theclosure of relay 353 does not bring about the closure of relay 364.

With the plus pulse on the grid of tube V6, the tube is made conductive.The circuitry arrangement between tubes V6 and V1 is similar to thatbetween V7 and tube V4. In other words, when tube V6 is made conductive,the cathode of tube V1 rises to about plus twenty volts, through line376. The grid of V1 is supplied with twenty volts positive currentthrough resistors 377, 378, and V1 will continue to be conductive untilthe plate of V6 is grounded by energization of relay 305, or by thereduction of voltage on the grid of V1, which is brought about by theclosure of the pulser contacts 336. When V1 is rendered non-conductive,its plate goes positive from the one hundred fifty volt plus supply,through resistor 380. The pulse is transmitted through capacitor 381,resistor 382, to the starting anode of the tube V2, causing it to fire.With V2 conducting, the relay 370 is energized, moving the contact 368into engagement with the contact 383. This disconnects the counter pulseline 367 from the line 281. The next pulse from 367 is applied to thegrid of tube V3, turning the tube on and closing relay 387 connected inits plate circuit. The resulting movement of contact 388 out ofengagement with contact 389, removes the plus supply to the plate oftube V2, rendering it non-conductive and causing relay 370 to drop out.By this time, the pulse from 367 has been dissipated and has not beentransmitted to the counter. This process is repeated by successiveclosures of the pulser contacts 336 until the counter tubes 60, 61,reach zero, not more than ten percent ahead of the master zero pulse, atwhich time the slot 36 in disk 23 has effected operation of the photocell 44, so that power is supplied to the line 59 to hold relay 364energized until the zero pulse comes from the master.

What I claim is:

1. A traffic signaling system for a multiplicity of intersectionscomprising:

(a) a cyclical master timer operable during each cycle of operation toproduce a zero control pulse, N equally-spaced stepping pulses, andphase control potentials respectively manifestive of the two halves ofthe master timer cycle on each of a plurality of output lines;

(b) a single cyclical pulse counter associated with the signalcontroller at each intersection, and operable to advance one count foreach stepping pulse received thereby, and to manifest all counts betweenzero and N counts;

(c) first settable means at each controller for predetermining the countin said counter at which each one of a series of trafiic movements isintended to begin;

(d) means interconnecting said first settable means and said counter,and operable responsive to a coincidence between the respective presetcounts and the count manifested in said counter for activating eachrespective one of the sequential traffic movements;

(e) second settable means at each controller for presetting the desiredphase relationship, otfst, of the cycle of said counter with respect tothe cycle of said master timer;

(f) a communication link connecting the outputs from said master timerwith the controller at each intersection and operable to transmit saidzero control pulse, said stepping pulses, and said phase controlpotentials;

(g) means interconnecting said counting means and said second settablemeans for producing a unique signal only when the count in said counterequals the preset value in said second settable means;

(h) normally active means connecting said stepping pulses to saidcounter to advance the count in said counter;

(i) means responsive to the lack of said unique signal and to one ofsaid phase potentials for rendering said normally active means inactiveto transmit stepping pulses to said counter when the counter leads thepreset phase relationship;

(j) means responsive to the lack of said unique signal and to the secondof said phase potentials for producing a control potential to advancethe counter at an accelerated rate; and

(k) a pulse-producing means operatively connected to said counter bysaid last-named control potential for advancing the counter; wherebysaid counter is maintained in the proper phase relationship and insynchronism with said master timer and provides the 1 1 1 2 sequence oftraflic movement controls at the requisite whereby the phase andsynchronism of the counter is preset times in the cycle. checked twiceduring each cycle.

2. The traffic signaling system of claim 1 wherein said master timer isadapted to produce a variable cycle length.

3. The traffic signaling system of claim 1 wherein said UNITED STATESPATENTS References Cited first settable means comprises a plugboard intowhich a 5 3 252133 5/1966 Auer 340 40 plurality Of diiferent timeCOUIIIS for initiation Of thB Same 3 25 134 5 19 6 Auer 340 35 trafiicmovement may be plugged, and means for remotely 3305828 2/1967 Auer 34040 selecting one of the plurality of preplugged counts for control. 10THOMAS B. HABECKER, Primary Examiner 4. The traflic signaling system ofclaim 1 wherein said second settable means includes a true countmanifestation C XR and a manifestation of N/2 plus the truemanifestation -166

